1 files changed, 145 insertions, 0 deletions
diff --git a/src/test/java/com/google/devtools/build/lib/rules/objc/RuleType.java b/src/test/java/com/google/devtools/build/lib/rules/objc/RuleType.java
new file mode 100644
index 0000000000..18875c680d
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/rules/objc/RuleType.java
@@ -0,0 +1,145 @@
+// Copyright 2017 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.rules.objc;
+
+import com.google.common.base.Joiner;
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.testutil.Scratch;
+import com.google.devtools.build.lib.util.Preconditions;
+import java.io.IOException;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Provides utilities to help test a certain rule type without requiring the calling code to know
+ * exactly what kind of rule is being tested. Only one instance is needed per rule type (e.g. one
+ * instance for {@code objc_library}).
+ */
+public abstract class RuleType {
+  /**
+   * What to pass as the value of some attribute to indicate an attribute should not be added to the
+   * rule. This can either be to test an error condition, or to use an alternative attribute to
+   * supply the value.
+   */
+  public static final String OMIT_REQUIRED_ATTR = "<OMIT_REQUIRED_ATTR>";
+
+  private final String ruleTypeName;
+
+  RuleType(String ruleTypeName) {
+    this.ruleTypeName = ruleTypeName;
+  }
+
+  /**
+   * The name of this type as it appears in {@code BUILD} files, such as {@code objc_library}.
+   */
+  final String getRuleTypeName() {
+    return ruleTypeName;
+  }
+
+  /**
+   * Returns whether this type exports companion library target in Xcode.
+   */
+  final boolean exportsXcodeCompanionTarget() {
+    return ruleTypeName.equals("objc_binary");
+  }
+
+  /**
+   * Returns the bundle extension for the bundles generated by the rule.
+   */
+   final String bundleExtension() {
+     return ruleTypeName.equals("ios_test") ? "xctest" : "app";
+   }
+
+  /**
+   * Returns names and values, and otherwise prepares, extra attributes required for this rule type
+   * to be without error. For instance, if this rule type requires 'srcs' and 'infoplist'
+   * attributes, this method may be implemented as follows:
+   * <pre>
+   * {@code
+   * List<String> attributes = new ArrayList<>();
+   * if (!alreadyAdded.contains("srcs")) {
+   *   scratch.file("/workspace_root/" + packageDir + "/a.m");
+   *   attributes.add("srcs = ['a.m']");
+   * }
+   * if (!alreadyAdded.contains(INFOPLIST_ATTR)) {
+   *   scratch.file("/workspace_root/" + packageDir + "Info.plist");
+   *   attributes.add("infoplist = ['Info.plist']");
+   * }
+   * return attributes;
+   * </pre>
+   * }
+   *
+   * @throws IOException for whatever reason the implementator feels like, but mostly just when
+   *     a scratch file couldn't be created
+   */
+  abstract Iterable<String> requiredAttributes(
+      Scratch scratch, String packageDir, Set<String> alreadyAdded) throws IOException;
+
+  private ImmutableMap<String, String> map(String... attrs) {
+    ImmutableMap.Builder<String, String> map = new ImmutableMap.Builder<>();
+    Preconditions.checkArgument((attrs.length & 1) == 0,
+        "attrs must have an even number of elements");
+    for (int i = 0; i < attrs.length; i += 2) {
+      map.put(attrs[i], attrs[i + 1]);
+    }
+    return map.build();
+  }
+
+  /**
+   * Generates the String necessary to define a target of this rule type.
+   *
+   * @param packageDir the package in which to create the target
+   * @param name the name of the target
+   * @param checkSpecificAttrs alternating name/values of attributes to add to the rule that are
+   *     required for the check being performed to be defined a certain way. Pass
+   *     {@link #OMIT_REQUIRED_ATTR} for a value to prevent an attribute from being automatically
+   *     defined.
+   */
+  final String target(
+      Scratch scratch, String packageDir, String name, String... checkSpecificAttrs)
+      throws IOException {
+    ImmutableMap<String, String> checkSpecific = map(checkSpecificAttrs);
+    StringBuilder target = new StringBuilder(ruleTypeName)
+        .append("(name = '")
+        .append(name)
+        .append("',");
+    for (Map.Entry<String, String> entry : checkSpecific.entrySet()) {
+      if (entry.getValue().equals(OMIT_REQUIRED_ATTR)) {
+        continue;
+      }
+      target.append(entry.getKey())
+          .append("=")
+          .append(entry.getValue())
+          .append(",");
+    }
+    Joiner.on(",").appendTo(
+        target,
+        requiredAttributes(scratch, packageDir, checkSpecific.keySet()));
+    target.append(')');
+    return target.toString();
+
+  }
+
+  /**
+   * Creates a target at //x:x which is the only target in the BUILD file. Returns the string that
+   * is written to the scratch file as it is often useful for debugging purposes.
+   */
+  public final String scratchTarget(Scratch scratch, String... checkSpecificAttrs)
+      throws IOException {
+    String target = target(scratch, "x", "x", checkSpecificAttrs);
+    scratch.file("x/BUILD", target);
+    return target;
+  }
+}